Instantaneous steam boiler

ABSTRACT

The present invention relates to an instantaneous steam boiler generating steam in a steam cleaner, a steam-vacuum cleaner, a steam iron, etc. The instantaneous steam boiler has a substantially short traveling path of water against the formation of fur by insertedly molding a separate flow tube while being in contact with a U-shaped heater.

CROSS-REFERENCE(S) TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION

The present invention relates to an instantaneous steam boiler generating steam in a steam cleaner, a steam-vacuum cleaner, a steam iron, etc. More specifically, the present invention relates to an instantaneous steam boiler featuring a substantially short traveling path of water against the formation of fur by insertedly molding a separate flow tube while being in contact with a U-shaped heater.

Steam boilers are largely classified into reservoir type water heaters and instantaneous water heaters. The reservoir type water heater has an electric boiler built in a water tank. By heating the steam boiler, water temperature increases and the heated water finally generates steam (vapor). The steam is then discharged through a steam outlet on the top of the water tank. On the other hand, the instantaneous water heater has a water tank and a steam boiler, which are separately installed. In such system, water is transferred from the water tank toward the steam boiler with aid of a pump located between the water tank and the steam boiler.

The instantaneous water heater is built in a body made of a thermoconductive metal such as aluminum having a water transfer tube (or hose) formed therein. When the heater temperature increases, its heat is transferred to the body and water traveling inside the transfer tube in the body is eventually converted into steam. That is to say, as shown in FIG. 8 and FIG. 9, a conventional instantaneous steam boiler is provided with a body forming a water transfer tube and including an inlet 22 for water and an outlet 23 for steam formed on both ends of the transfer tube and a built-in heater 25. The body is divided into a first body 10 and a second body 20 connected to the first body 10 to form the transfer tube, and a packing 30 for preventing leakage of water from the tube is interposed between the first body 10 and the second body 20. The heater 25 is built in the second body 20, and a plurality of projections 26 are formed protrusively on a bottom surface of a transfer tube forming portion 21.

These projections 26 interfere with rapid flow of water to increase contact time between water and the body and increase a heat transfer area of between water and the body, so that steam may be generated in a stable manner.

However, since heat is transferred from the heater 25 to the transfer tube (i.e., conduction system), the transfer tube is typically made long (curved U-shape tube) and wide in order to produce sufficient steam.

When the transfer tube has an extended length, it is more likely to retain water therein and fur exposure is inevitable. That is to say, it is rather natural that the transfer tube constantly being exposed to water is furred up (because of the presence of impurities) or has an oxidation coating or scale (which is a thin film of an oxide formed on the surface of metal in result of chemical reaction) especially when the tube is made out of metal. Such fur or oxidation coating is descaled when it reaches a certain thickness. Unfortunately though, this descaled fur or oxidation coating is particularly fatal to the instantaneous steam boiler. Because a steam outlet of the instantaneous steam boiler normally has a small volume and a very small diameter, the boiler may easily get clogged up, producing steam in an unstable and non-uniform manner and losing pump pressure. These drawbacks are led to a serious deterioration in the durability of the steam boiler.

In addition, a complicated mold structure is required to form the projections 26 and a separate process needs to be done in order to connect/separate an upper and a lower body.

Normally, a suitable temperature for generating steam ranges from 130 to 140° C. To this end, 1200-1300 watts of power should be applied to the heater. If the tube of the heater is 7Φ in diameter, it is approximately 22 cm long. Since this is quite long, the tube has to be bent into U-shape. Still, the tube has a length of 10 cm, occupying a substantial portion of the space.

As a counter scheme, some instantaneous steam boilers have linear transfer tubes for their bodies. This body of a linear transfer tube is also obtained by connecting/assembling two parts (upper and lower parts). Even though the transfer path became shorter than the U-shaped tube described above, since the same heat transfer method was adopted, the tube was made either broader or deeper as much as it got relatively shorter in length. Therefore, water is left to stand in the tube for an extended period, and similar to before, the tube may readily be clogged up with fur or oxidation coatings.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an instantaneous steam boiler, which is manufactured in a very simple molding structure and through a very simple process and which has a substantially reduced traveling path of water by coming in a contact with a heater, whereby the formation of fur or an oxidation coating can be suppressed as much as possible.

In accordance with the present invention, there is provided an instantaneous steam boiler, including: a heater, a flow tube having a water inlet and a steam outlet, and a body embedded in a way to expose ports of the heater and the water inlet and the steam outlet of the flow tube.

According to the exemplary embodiment described above, because the body is molded with the heater and the flow tube already embedded, a molding structure is very simple and the body can be manufactured by an one-step process, eliminating an assembly/disassembly process.

Since the flow tube and the heater are embedded in the body while being in contact with each other, the transfer path of the flow tube is substantially reduced through the contact with the heater and water does not remain stationed in the tube. This in turn makes it possible to suppress the formation of fur or an oxidation coating as much as possible.

Preferably, the body is molded with the heater and the flow tube already inserted.

Moreover, with the U-shaped transfer tube, the contact efficiency between the tube and the heater increases, and a steam boiler incorporating such tube does not occupy a lot of space but is easily installed in a small space.

Particularly, if the flow tube is made out of copper materials, it demonstrates excellent heat conductivity. Therefore, steam can be supplied in a stable manner even when the flow tube length is reduced even further.

The other objectives and advantages of the invention will be understood by the following description and will also be appreciated by the embodiments of the invention more clearly. Further, the objectives and advantages of the invention will readily be seen that they can be realized by the means and its combination specified in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 through FIG. 7 respectively illustrate a perspective view of an instantaneous steam boiler, according to various embodiments of the present invention;

FIG. 8 is an exploded perspective view of a conventional steam boiler; and

FIG. 9 is a cross-sectional view taken along line A-A of FIG. 8.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be set forth in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the invention.

Embodiment I

FIG. 1 is a perspective view of an instantaneous steam boiler with a heater and a flow tube arranged 180 degrees apart, facing opposite directions.

Referring to FIG. 1, a steam boiler 100 according to a first embodiment of the present invention is constituted by a U-shaped heater 110, a flow tube 130, and a body 150 for housing parts of them 110 and 130.

Because the flow tube 130 is separately embedded in the body 150, a molding process of the body for forming a complicated flow path is much simplified, compared with a conventional technique.

The heater 110 is preferably formed into a U shape. That is, the heater 110 is composed of a first linear portion 111 and a second linear portion 113 in parallel to each other and an arc-shaped return portion 115. Ports 112 and 114 are formed at the other ends of the first linear portion 111 and the second linear portion 113.

Similar to the heater 110, the flow tube 130 is preferably formed into a U shape. One end of the flow tube 130 functions as an inlet 131 for water and the other end functions as an outlet 133 for steam. Of course, the flow tube 130 may have a linear shape, but in such case its contact efficiency with the heater 110 is not good compared with the U-shaped tube and its extended length occupies a large portion of a defined space, together making a linear flow tube less favorable.

Moreover, the flow tube 130 and the heater 110 are arranged 180 degrees apart, facing opposite directions, with the flow tube 130 lying upon on top of the heater 110. In the drawing, the water inlet 131 and the steam outlet 133 of the flow tube 130 are arranged on the left hand side, while the ports 112 and 114 on the right hand side.

As the flow tube 130 and the heater 110 are brought into contact with each other, heat transfer to the flow tube 130 is done by direct heating, not by conduction, convection, or radiation. Therefore, even though the length of the flow tube 130, i.e., the traveling path of water, may be reduced substantially, high evaporation rate makes it possible to discharge steam. In this manner, since water is not left to stand in the tube, the steam outlet 133 can be kept from getting clogged up by fur or an oxidation coating.

Further, because the flow tube 130 and the heater 110 are in contact with each other, it is possible to mold the body 150 as one unit with the flow tube 130 and the heater 110 already inserted. That is to say, the heater 110 and the flow tube 130 lying upon the top of the heater 110 are tied up with a binding twine for example. The heater 110 and the flow tube 130 being tied up together are then inserted to a mold for forming the body 150. In so doing, the water inlet 131 and steam outlet 133 of the flow tube 130 and the ports 112 and 114 of the heater 110 are embedded in the body 150, while part of each being exposed to outside. The body 150 is obtained by die casting or injection molding.

Therefore, the one unit body eliminates an assembly/disassembly process and improves productivity.

Preferably, the flow tube 130 is made out of copper material. Copper is nontoxic and demonstrates a high corrosion resistance and an excellent thermal conductivity so it contributes not only to a decrease in the length of the flow tube 130 but also to a substantial improvement on the evaporation rate (or water vaporization rate).

As such, with the separate flow tube 130 being in contact with the heater 110 in the steam boiler 100, the traveling path of water is markedly reduced and evaporation rate is increased even more. This enables to expand the diameters of the water inlet 131 and steam outlet 133, compared with the conventional ones.

The diameter of the water inlet 131 is closely related to an amount of water input. Therefore, provided that the same amount of water is fed, an increased diameter can lower pump pressure, thereby reducing noises or vibrations as much as possible. Also, the wider steam outlet 133 allows the steam to easily escape despite the presence of small impurities in water, so the tube is hardly clogged up.

Embodiment II

FIG. 2 is a perspective view of an instantaneous steam boiler in accordance with a second embodiment of the present invention.

As shown in FIG. 2, although similar in structure and functions, a steam boiler 200 of the second embodiment differs from the steam boiler 100 of the first embodiment by an orthogonal arrangement of a flow tube 230 with respect to a heater 110.

By placing the flow tube 230 at right angles to the heater 110, it becomes possible to adjust the gap between a water inlet 231 and a steam outlet 233 of the flow tube 230, thereby expanding the limit of the layout area for product design.

Embodiment III

FIG. 3 is a perspective view of an instantaneous steam boiler in accordance with a third embodiment of the present invention.

As shown in FIG. 3, although similar in structure and functions, a steam boiler 300 of the third embodiment differs from the steam boiler 200 of the second embodiment in that a return portion 331 of a flow tube 330 is in a coiled form and a heater 110 is orthogonally arranged inside the coil.

Embodiment IV

FIG. 4 is a perspective view of an instantaneous steam boiler in accordance with a fourth embodiment of the present invention.

As shown in FIG. 4, although similar in structure and functions, a steam boiler 400 of the fourth embodiment differs from the steam boiler 100 of the first embodiment in that a return portion 415 of a heater 410 is in a twisted form.

The heaters 110 in the first through third embodiments are 7Φ wide and about 10 cm long, but length ‘a’ of a heater 410 according to the fourth embodiment is reduced as much as a twisted length of a return portion 415. Therefore, because a body 450 now has a smaller size to fit in a narrow space, small and light products can be manufactured.

That is, in case of a steam cleaner, a steam boiler is built in a main body with a bottom or is installed at an extension bar. When the steam boiler is built in the main body, the size of the main body is increased especially if the body 450 is large by itself. This makes it difficult to clean the gap between the steam boiler and the body. The space becomes even smaller when the main body is designed as a vacuum cleaner as well. Meanwhile, when the steam boiler is installed at the extension bar, it creates a large-size steam boiler that does not look stylish or neat in design.

From these aspects, the coiled or twisted return portion 415 of the heater 410 is a first optimization process for producing small, light appliances.

Moreover, the flow tube 430 can be made shorter as much as the reduced length of the body 450.

It is also evident to people skilled in the art that the length of the heater 410 can be reduced by bending the return portion 415 of the heater 410 into a U-shape, not the twisted shape (the overall shape of the heater is an M-shape).

The operational effects of the heater 410 of the fourth embodiment are same whether it is installed at a separate flow tube or whether it is built in a steam boiler with a body and a flow tube combined as one unit.

Embodiment V

FIG. 5 is a perspective view of an instantaneous steam boiler in accordance with a fifth embodiment of the present invention.

As shown in FIG. 5, although similar in structure and functions, a steam boiler 100′ of the fifth embodiment differs from the steam boiler 100 of the first embodiment in that a return portion 135′ of a flow tube 130′ is curved into a circle.

Embodiment VI

FIG. 6 is a perspective view of an instantaneous steam boiler in accordance with a sixth embodiment of the present invention.

As shown in FIG. 6, although similar in structure and functions, a steam boiler 200′ of the sixth embodiment differs from the steam boiler 200 of the second embodiment in that a return portion 235′ of a flow tube 230′ is in a curved-corner square shape.

Embodiment VII

FIG. 7 is a perspective view of an instantaneous steam boiler in accordance with a seventh embodiment of the present invention.

As shown in FIG. 7, although similar in structure and functions, a steam boiler 400′ of the seventh embodiment differs from the steam boiler 400 of the fourth embodiment in that a return portion 435′ of a flow tube 430′ is curved into an oval shape and a water inlet 431′ and a steam outlet 433′ are aligned at the ends of the heater 410.

As has been explained so far, the instantaneous steam boiler of the present invention has the following advantages.

Because a part of the flow tube and of the heater are embedded in the body, a complicate mold for forming a flow path in the body itself is no longer required to thereby increase productivity and economic efficiency.

In addition, by embedding the flow tube and the heater while being in contact with each other, heat transfer to the flow tube is done by direct heating, not by conduction, convection, or radiation. Therefore, even though the traveling path of water may be reduced substantially, water evaporation still takes place and water is not left to stand in the tube. Consequently, the steam outlet can be kept from getting clogged up by fur or an oxidation coating.

Moreover, because the flow tube and the heater are inserted to a mold for the body while they are in contact with each other, an assembly/disassembly process is no longer required and such a simple structure of the molding for the body can markedly lower manufacturing costs.

Besides, the U-shaped flow tube features a high contact efficiency with the heater yet occupies a small portion of the space defined in the product, resulting in a substantial decrease in manufacturing costs.

Also, the flow tube is made out of copper material which is nontoxic and demonstrates a high corrosion resistance and an excellent thermal conductivity. Therefore, even though the length of the flow tube may be shortened even further, steam can be supplied in a stable manner.

While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. 

1. An instantaneous steam boiler, comprising: a heater; a flow tube with a water inlet and a steam outlet; and a body embedded in a manner to expose ports of the heater and the water inlet and the steam outlet of the flow tube.
 2. The instantaneous steam boiler according to claim 1, wherein the flow tube is embedded in the body while being in contact with the heater.
 3. The instantaneous steam boiler according to claim 2, wherein the body is molded with the heater and the flow tube already inserted, and the flow tube is formed into a U-shape.
 4. The instantaneous steam boiler according to claim 1, wherein the flow tube is made out of a copper material. 